Turnbuckles in use, are often subjected to vibration or other forces tending to gradually loosen the turnbuckle. Particularly in marine installations such as sailboats, turnbuckles are employed for tensioning stays coupled at one end to the sailboat deck, and at an opposite end to the sailboat mast. When such sailboats are subjected to high wind conditions, the turnbuckles rapidly loosen.
To combat such problems, turnbuckles in the past have been provided with jam nuts. The jam nuts are tightened against the body of the turnbuckle. Opposite handed threaded shanks are threaded within aligned tapped holes within opposite ends of the turnbuckle body. By rotation of the jam nuts, into frictional contact with the turnbuckle body end walls, the threaded shanks are maintained in an axially set position. However, the tightening of such jam nuts involves an expenditure of extra time and effort in setting the turnbuckle and is generally inconvenient to the user.
Various alternative means have been employed for locking the turnbuckle with the threaded shanks in a proper position and with the stays or other tensioned members set at a predetermined, proper tension. Such locking or latching arrangements for turnbuckles are exemplified by U.S. Pat. No. 2,278,320 to H. K. Kath entitled "Locking Turnbuckle" and issued Mar. 31, 1942; U.S. Pat. No. 2,479,172 to R. W. Landon issued Aug. 16, 1949 and entitled "Turnbarrel Connection"; U.S. Pat. No. 2,512,501 to A. W. Miller issued Jun. 20, 1950 entitled "Turnbuckles"; U.S. Pat. No. 3,806,265 to Mark Hattan issued Apr. 23, 1974 entitled "Self-Locking Turnbuckle"; U.S. Pat. No. 3,851,978 to Sytze Kuipers issued Dec. 3, 1974 and entitled "Turnbuckle"; and U.S. Pat. No. 4,297,046 to Roy F. McGill issued Oct. 27, 1981 and entitled "Turnbuckle".
Such latching or locking turnbuckles are fairly complex, require elements in addition to the basic turnbuckle body and axially rotatable opposite hand threaded elements coaxially mounted to tapped bores within the end walls of the turnbuckle body while tending to interfere with the normal rotation of the threaded elements to increase or decrease the tension within the system bearing the turnbuckle.
Conventionally cotter pins are positioned within radial holes within the threaded rod ends borne by the tapped holes of the open rectangular frame turnbuckle body, after the turnbuckle is tightened to the desired degree of tension for the system connected by the turnbuckle. The cotter pins have free extending radially outwardly of radial hole within the rod end beyond the outer surface of the threaded rod ends, and contact with a side wall of the open, rectangular frame body prevent rotation of the rod ends within the body.
However, where cotter pins are employed as the locking means for the turnbuckle threaded rod ends, each time the tension of the stayed system requires change, the split free ends of the cotter pin must be pinched together, the cotter pin removed, adjustment made by relative rotation of the threaded rod ends and the rectangular turnbuckle frame body and then replacement of the cotter pin and re-flaying of the split ends (if possible) or replacement by a new cotter pin. Again, such action requires time, tools, and manual dexterity. Where the sailboat or yacht takes the form of a racing yacht, retuning of the rig (mast supporting structure) may occur before each race or after a given series of races.
It is therefore, a primary object of the present invention to eliminate cotter pins as a locking means for turnbuckles, particularly for turnbuckles for use in tensioning a sailboat mast stay system and which employs a simplified lock system into threaded rod ends, in the form of a rotatable lock plate which rotates from an in-line position with the axis of the threaded rod ends, to one at some angle thereto, which is frictionally restrained in both the latched and unlatched positions and which may be shifted between the latched and unlatched position by a simple tool such as a screwdriver, and which does not impede change in tensioning of the system to which the turnbuckle is coupled during relative rotation of the open, rectangular frame body with respect to the threaded rod ends carrying the pivotable lock plates.